PCI Express 5.0 x8 interface paired with PCI Express 4.0 x16 slot
PCI Express 5.0 x8 interface paired with PCI Express 4.0 x16 slot
I'm trying to understand how the PCIe slots behave when they change sizes. With Motherboards, the PCIE 5.0 x16 slots are being replaced by PCIE 5.0 x8 when a shared slot is used. I want to know what happens physically if a PCIE 4.0 X16 card is connected. I'm sure it will still work, but does using an x8 slot mean the x4 card becomes an x8 card? Should the extra connections be turned off or is there a mechanism that adjusts the bandwidth without changing the pin count?
When the slot has eight lanes, it operates at the maximum speed possible with both the GPU and the slot capabilities. In this case, the GPU would handle four lanes simultaneously at 4.0 x8, which matches the performance of three lanes at 16x (3.0 x16) and won't cause any bottlenecks, even with a high-end Rtx 4090.